Effect of national immunisation campaigns with oral polio vaccine on all-cause mortality in children in rural northern Ghana: 20 years of demographic surveillance cohort data.

Background: Studies from Guinea-Bissau and Bangladesh have shown that campaigns with oral polio vaccine (C-OPV) may be associated with 25-31% lower child mortality. Between 1996 and 2015, Ghana had 50 national C-OPVs and numerous campaigns with vitamin A supplementation (VAS), and measles vaccine (MV). We investigated whether C-OPVs had beneficial non-specific effects (NSEs) on child survival in northern Ghana. Methods: We used data from a health and demographic surveillance system in the Navrongo Health Research Centre in rural northern Ghana to examine mortality from day 1-5 years of age. We used Cox models with age as underlying time scale to calculate hazard ratios (HR) for the time-varying covariate "after-campaign" mortality versus "before-campaign" mortality, adjusted for temporal change in mortality, other campaign interventions and stratified for season at risk. Findings: From 1996 to 2015, 75,610 children were followed for 280,156 person-years between day 1 and 5 years of age. In initial analysis, assuming a common effect across all ages, we did not find that OPV-only campaigns significantly reduced all-cause mortality, the HR being 0.96 (95% CI: 0.88-1.05). However, we subsequently found the HR differed strongly by age group, being 0.92 (0.75-1.13), 1.29 (1.10-1.51), 0.79 (0.66-0.94), 0.67 (0.53-0.86) and 1.03 (0.78-1.36) respectively for children aged 0-2, 3-5, 6-8, 9-11 and above 12 months of age (p < 0.001). Triangulation of the evidence from this and previous studies suggested that increased frequency of C-OPVs and a different historical period could explain these results. Interpretation: In Ghana, C-OPVs had limited effects on overall child survival. However, triangulating the evidence suggested that NSEs of C-OPVs depend on age of first exposure and routine vaccination programs. C-OPVs had beneficial effects for children that were not exposed before 6 months of age. These non-specific effects of OPV should be exploited to further reduce child mortality. Funding: DANIDA; Else og Mogens Wedell Wedellsborgs Fond.

Disruptions to healthcare quality and early child health outcomes: Evidence from health-worker strikes in Kenya.

This paper measures the effects of disruptions to healthcare quality at birth on early child health outcomes in Kenya. To identify impacts, we exploit variation in the timing and location of health-worker strikes at individual hospitals across the country between 1999 and 2014. Using data from Demographic Health Surveys, we find that children born during strikes are more likely to suffer a neonatal death. We find similar results using separate data collected in two informal settlements in Nairobi located near hospitals with frequent strikes. These results show that interruptions to healthcare quality can have large immediate health impacts, and suggests that status quo hospital care provides positive benefits. We also find suggestive evidence of reductions in later health investments, measured by vaccine take-up, among those who survive. This study provides the first rigorous evidence on the consequences of health-worker strikes, a frequent but understudied phenomenon in Sub-Saharan Africa.

Health service utilisation during the COVID-19 pandemic in sub-Saharan Africa in 2020: a multicountry empirical assessment with a focus on maternal, newborn and child health services.

INTRODUCTION: There are concerns about the impact of the COVID-19 pandemic on the continuation of essential health services in sub-Saharan Africa. Through the Countdown to 2030 for Women's, Children's and Adolescents' Health country collaborations, analysts from country and global public health institutions and ministries of health assessed the trends in selected services for maternal, newborn and child health, general service utilisation. METHODS: Monthly routine health facility data by district for the period 2017-2020 were compiled by 12 country teams and adjusted after extensive quality assessments. Mixed effects linear regressions were used to estimate the size of any change in service utilisation for each month from March to December 2020 and for the whole COVID-19 period in 2020. RESULTS: The completeness of reporting of health facilities was high in 2020 (median of 12 countries, 96% national and 91% of districts ≥90%), higher than in the preceding years and extreme outliers were few. The country median reduction in utilisation of nine health services for the whole period March-December 2020 was 3.9% (range: -8.2 to 2.4). The greatest reductions were observed for inpatient admissions (median=-17.0%) and outpatient admissions (median=-7.1%), while antenatal, delivery care and immunisation services generally had smaller reductions (median from -2% to -6%). Eastern African countries had greater reductions than those in West Africa, and rural districts were slightly more affected than urban districts. The greatest drop in services was observed for March-June 2020 for general services, when the response was strongest as measured by a stringency index. CONCLUSION: The district health facility reports provide a solid basis for trend assessment after extensive data quality assessment and adjustment. Even the modest negative impact on service utilisation observed in most countries will require major efforts, supported by the international partners, to maintain progress towards the SDG health targets by 2030.

Patterns and predictors of private and public health care utilization among residents of an informal settlement in Nairobi, Kenya: a cross-sectional study.

BACKGROUND: Knowledge of health care utilization is important in low-and middle-income countries where inequalities in the burden of diseases and access to primary health care exist. Limited evidence exists on health seeking and utilization in the informal settlements in Kenya. This study assessed the patterns and predictors of private and public health care utilization in an urban informal settlement in Kenya. METHODS: This study used data from the Lown scholars study conducted between June and July 2018. A total of 300 households were randomly selected and data collected from 364 household members who reported having sought care for an illness in the 12 months preceding the study. Data were collected on health-seeking behaviour and explanatory variables (predisposing, enabling, and need factors). Health care utilization patterns were described using proportions. Predictors of private or public health care use were identified using multinomial logistic regression with the reference group being other providers. RESULTS: Majority of the participants used private (47%) and public facilities (33%) with 20% using other providers including local pharmacies/drug shops and traditional healers. In the model comparing public facilities vs other facilities, members who were satisfied with the quality of health care (vs not satisfied) were less likely to use public facilities (adjusted relative risk ratio (aRRR) 0.29; CI 0.11-0.76) while members who reported an acute infection (vs no acute infection) were more likely to use public facilities (aRRR 2.31; 95% CI 1.13-4.99) compared to other facilities. In the second model comparing private facilities to other facilities, having health insurance coverage (aRRR 2.95; 95% CI 1.53-5.69), satisfaction with cost of care (aRRR 2.08; CI 1.00-4.36), and having an acute infection (aRRR 2.97; 95% CI 1.50-5.86) were significantly associated with private facility use compared to other facilities. CONCLUSIONS: The majority of urban informal settlement dwellers seek care from private health facilities. As Kenya commits to achieving universal health coverage, interventions that improve health care access in informal and low-resource settlements are needed and should be modelled around enabling and need factors, particularly health care financing and quality of health care.

Economic valuation of setting up a social health enterprise in urban poor-resource setting in Kenya.

The failure of the market and government to provide quality healthcare services have been the motivation to set up social health enterprise. However, the value for money associated with setting up a social health enterprise in sub-Sahara African countries has been relatively unexplored in the literature. The study presents the first empirical estimates of the mean willingness-to-pay (WTP) for setting up a social health enterprise that will simultaneously run a health center and provide health insurance scheme in an urban resource-poor setting and explores whether the benefits outweigh the costs. The contingent valuation method is used to estimate the mean WTP for the health insurance scheme proposed by the social health enterprise in Viwandani slum (Nairobi, Kenya). The survey was conducted between June and July 2018 on 300 households. We find that the feasibility of setting up a social health enterprise could be promising with 97 percent of respondents willing to pay about US$ 2 per person per month for a scheme that would provide quality healthcare services. More importantly, setting up the social health enterprise will yield a positive net profit, and investors could expect US$ 1.11 in benefits for each US$ 1 of costs of investment in setting up the social health enterprise. We, therefore, conclude that this health policy in this urban resource-poor setting could be a viable solution to reach the neglected urban households in the Kenyan slums.

Access to primary healthcare services and associated factors in urban slums in Nairobi-Kenya.

BACKGROUND: Access to primary healthcare is crucial for the delivery of Kenya's universal health coverage policy. However, disparities in healthcare have proved to be the biggest challenge for implementing primary care in poor-urban resource settings. In this study, we assessed the level of access to primary healthcare services and associated factors in urban slums in Nairobi-Kenya. METHODS: The data were drawn from the Lown scholars' study of 300 randomly selected households in Viwandani slums (Nairobi, Kenya), between June and July 2018. Access to primary care was measured using Penchansky and Thomas' model. Access index was constructed using principal component analysis and recorded into tertiles with categories labeled as poor, moderate, and highest. Generalized ordinal logistic regression analysis was used to determine the factors associated with access to primary care. The adjusted odds ratios (AOR) and 95% confidence intervals were used to interpret the strength of associations. RESULTS: The odds of being in the highest access tertile versus the combined categories of lowest and moderate access tertile were three times higher for males than female-headed households (AOR 3.05 [95% CI 1.47-6.37]; p < .05). Households with an average quarterly out-of-pocket healthcare expenditure of ≥USD 30 had significantly lower odds of being in the highest versus combined categories of lowest and moderate access tertile compared to those spending ≤ USD 5 (AOR 0.36 [95% CI 0.18-0.74]; p < .05). Households that sought primary care from private facilities had significantly higher odds of being in the highest versus combined categories of lowest and moderate access tertiles compared to those who sought care from public facilities (AOR 6.64 [95% CI 3.67-12.01]; p < .001). CONCLUSION: In Nairobi slums in Kenya, living in a female-headed household, seeking care from a public facility, and paying out-of-pocket for healthcare are significantly associated with low access to primary care. Therefore, the design of the UHC program in this setting should prioritize quality improvement in public health facilities and focus on policies that encourage economic empowerment of female-headed households to improve access to primary healthcare.

Large and persistent subnational inequalities in reproductive, maternal, newborn and child health intervention coverage in sub-Saharan Africa.

Subnational inequalities have received limited attention in the monitoring of progress towards national and global health targets during the past two decades. Yet, such data are often a critical basis for health planning and monitoring in countries, in support of efforts to reach all with essential interventions. Household surveys provide a rich basis for interventions coverage indicators on reproductive, maternal, newborn and child health (RMNCH) at the country first administrative level (regions or provinces). In this paper, we show the large subnational inequalities that exist in RMNCH coverage within 39 countries in sub-Saharan Africa, using a composite coverage index which has been used extensively by Countdown to 2030 for Women's, Children's and Adolescent's Health. The analyses show the wide range of subnational inequality patterns such as low overall national coverage with very large top inequality involving the capital city, intermediate national coverage with bottom inequality in disadvantaged regions, and high coverage in all regions with little inequality. Even though nearly half of the 34 countries with surveys around 2004 and again around 2015 appear to have been successful in reducing subnational inequalities in RMNCH coverage, the general picture shows persistence of large inequalities between subnational units within many countries. Poor governance and conflict settings were identified as potential contributing factors. Major efforts to reduce within-country inequalities are required to reach all women and children with essential interventions.

Barriers and facilitators to care-seeking among survivors of gender-based violence in the Dadaab refugee complex.

In humanitarian settings, timely access to care is essential for survivors of gender-based violence (GBV). Despite the existence of GBV support services, challenges still exist in maximising benefits for survivors. This study aimed to understand the characteristics of violence against women and explore barriers and facilitators to care-seeking for GBV by women in two camps within the Dadaab refugee complex in Kenya. A mixed-methods design was used to study women accessing comprehensive GBV services between February 2016 and February 2017. Women were recruited into a cohort study (n = 209) and some purposively selected for qualitative in-depth interviews (n = 34). Survivor characteristics were descriptively analysed from baseline measures, and interview data thematically assessed. A majority of women were Muslim, of Somali origin, had been residents in the camp for more than five years, with little or no formal education, and meagre or no monthly income. From the survey, 60.3% and 66.7% of women had experienced non-partner violence or intimate partner violence in their lifetime respectively. Facilitators to accessing GBV services by survivors included awareness of GBV services and self-perceived high severity of acts of violence. Barriers included stigma by family and the community, fear of further violence from perpetrators, feelings of helplessness and insecurity, and being denied entry to service provision premises by guards. Women in the Dadaab refugee camps face violence from intimate partners, family, and other refugees. There is an urgent need to address drivers of GBV and the barriers to disclosure and access to services for all survivors of GBV.

Generating statistics from health facility data: the state of routine health information systems in Eastern and Southern Africa.

Health facility data are a critical source of local and continuous health statistics. Countries have introduced web-based information systems that facilitate data management, analysis, use and visualisation of health facility data. Working with teams of Ministry of Health and country public health institutions analysts from 14 countries in Eastern and Southern Africa, we explored data quality using national-level and subnational-level (mostly district) data for the period 2013-2017. The focus was on endline analysis where reported health facility and other data are compiled, assessed and adjusted for data quality, primarily to inform planning and assessments of progress and performance. The analyses showed that although completeness of reporting was generally high, there were persistent data quality issues that were common across the 14 countries, especially at the subnational level. These included the presence of extreme outliers, lack of consistency of the reported data over time and between indicators (such as vaccination and antenatal care), and challenges related to projected target populations, which are used as denominators in the computation of coverage statistics. Continuous efforts to improve recording and reporting of events by health facilities, systematic examination and reporting of data quality issues, feedback and communication mechanisms between programme managers, care providers and data officers, and transparent corrections and adjustments will be critical to improve the quality of health statistics generated from health facility data.

Trends of inequalities in childhood immunization coverage among children aged 12-23 months in Kenya, Ghana, and Côte d'Ivoire.

BACKGROUND: Immunization is one of the most cost-effective health intervention to halt the spread of childhood diseases, and improve child health. Yet, there is a substantial disparity in childhood immunization coverage. The overall objective of the study is to investigate the trends of within-country inequalities in childhood immunization coverage among children aged 12-23 months in Kenya, Ghana, and Côte d'Ivoire. The three countries included in this study are countries that are on the verge of entering the accelerated phase of the Gavi, the Vaccine Alliance's co-sharing of costs of vaccine and eventually assuming full costs of vaccines. Côte d'Ivoire is in the Gavi preparatory transition phase, entering the accelerated transition phase in 2020, with an expected transition to full self-financing in 2025. Ghana is expected to enter the accelerated transition phase in 2021 and to full self-financing in 2026 while Kenya will enter in 2022 and fully self-finance in 2027. We examine the pattern of inequality in childhood immunization coverage over time through an equity lens by mainly exploring the direction of inequality in coverage. METHODS: We use data from the Demographic Health Surveys and Multiple Indicator Cluster Surveys. The rate difference, rate ratio, and relative concentration index are used as measures of inequality. RESULTS: Results of the study suggest that in most years inequality in immunization coverage in the three countries persist over time, and it favors the most-advantaged households. However, there is a sharp decrease pattern in inequalities in childhood immunization coverage in Ghana over time. CONCLUSION: Policymakers could be more strategic in addressing pro-rich inequality in immunization coverage by designing health interventions through an equity lens. Using inequality data and putting disadvantaged households at the center of health intervention designs could increase the efficiency of the primary health care system and reduce the incidence of mortality and morbidity as a result of vaccine-preventable disease.

Fully immunized child: coverage, timing and sequencing of routine immunization in an urban poor settlement in Nairobi, Kenya.

BACKGROUND: More efforts have been put in place to increase full immunization coverage rates in the last decade. Little is known about the levels and consequences of delaying or vaccinating children in different schedules. Vaccine effectiveness depends on the timing of its administration, and it is not optimal if given early, delayed or not given as recommended. Evidence of non-specific effects of vaccines is well documented and could be linked to timing and sequencing of immunization. This paper documents the levels of coverage, timing and sequencing of routine childhood vaccines. METHODS: The study was conducted between 2007 and 2014 in two informal urban settlements in Nairobi. A total of 3856 children, aged 12-23 months and having a vaccination card seen were included in analysis. Vaccination dates recorded from the cards seen were used to define full immunization coverage, timeliness and sequencing. Proportions, medians and Kaplan-Meier curves were used to assess and describe the levels of full immunization coverage, vaccination delays and sequencing. RESULTS: The findings indicate that 67 % of the children were fully immunized by 12 months of age. Missing measles and third doses of polio and pentavalent vaccine were the main reason for not being fully immunized. Delays were highest for third doses of polio and pentavalent and measles. About 22 % of fully immunized children had vaccines in an out-of-sequence manner with 18 % not receiving pentavalent together with polio vaccine as recommended. CONCLUSIONS: Results show higher levels of missed opportunities and low coverage of routine childhood vaccinations given at later ages. New strategies are needed to enable health care providers and parents/guardians to work together to increase the levels of completion of all required vaccinations. In particular, more focus is needed on vaccines given in multiple doses (polio, pentavalent and pneumococcal conjugate vaccines).

Determinants of immunization inequality among urban poor children: evidence from Nairobi's informal settlements.

INTRODUCTION: Despite the relentless efforts to reduce infant and child mortality with the introduction of the National Expanded Programmes on Immunization (EPI) in 1974, major disparities still exist in immunizations coverage across different population sub-groups. In Kenya, for instance, while the proportion of fully immunized children increased from 57% in 2003 to 77% in 2008-9 at national level and 73% in Nairobi, only 58% of children living in informal settlement areas are fully immunized. The study aims to determine the degree and determinants of immunization inequality among the urban poor of Nairobi. METHOD: We used data from the Nairobi Cross-Sectional Slum Survey of 2012 and the health outcome was full immunization status among children aged 12-23 months. The wealth index was used as a measure of social economic position for inequality analysis. The potential determinants considered included sex of the child and mother's education, their occupation, age at birth of the child, and marital status. The concentration index (CI) was used to quantify the degree of inequality and decomposition approach to assess determinants of inequality in immunization. RESULTS: The CI for not fully immunized was -0.08 indicating that immunization inequality is mainly concentrated among children from poor families. Decomposition of the results suggests that 78% of this inequality is largely explained by the mother's level of education. CONCLUSION: There exists immunization inequality among urban poor children in Nairobi and efforts to reduce this inequality should aim at targeting mothers with low level of education during immunization campaigns.

Effects of low birth weight on time to BCG vaccination in an urban poor settlement in Nairobi, Kenya: an observational cohort study.

BACKGROUND: The World Health Organization recommends Bacillus Calmette-Guérin (BCG) vaccination against tuberculosis be given at birth. However, in many developing countries, pre-term and low birth weight infants get vaccinated only after they gain the desired weight. In Kenya, the ministry of health recommends pre-term and low birth weight infants to be immunized at the time of discharge from hospital irrespective of their weight. This paper seeks to understand the effects of birth weight on timing of BCG vaccine. METHODS: The study was conducted in two Nairobi urban informal settlements, Korogocho and Viwandani which hosts the Nairobi Urban Health and Demographic Surveillance system. All infants born in the study area since September 2006 were included in the study. Data on immunization history and birth weight of the infant were recorded from child's clinic card. Follow up visits were done every four months to update immunization status of the child. A total of 3,602 infants were included in this analysis. Log normal accelerated failure time parametric model was used to assess the association between low birth weight infants and time to BCG immunization. RESULTS: In total, 229 (6.4%) infants were low birth weight. About 16.6% of the low birth weight infants weighed less than 2000 grams and 83.4% weighed between 2000 and 2490 grams. Results showed that, 60% of the low birth weight infants received BCG vaccine after more than five weeks of life. Private health facilities were less likely to administer a BCG vaccine on time compared to public health facilities. The effects of low birth weight on females was 0.60 and 0.97-times that of males for infants weighing 2000-2499 grams and for infants weighing <2000 grams respectively. The effect of low birth weight among infants born in public health facilities was 1.52 and 3.94-times that of infants delivered in private health facilities for infants weighing 2000-2499 grams and those weighing < 2000 grams respectively. CONCLUSION: Low birth weight infants received BCG immunization late compared to normal birth weight infants. Low birth weight infants delivered in public health facilities were more likely to be immunized much later compared to private health facilities.

The non-specific effects of vaccines and other childhood interventions: the contribution of INDEPTH Health and Demographic Surveillance Systems.

Most childhood interventions (vaccines, micronutrients) in low-income countries are justified by their assumed effect on child survival. However, usually the interventions have only been studied with respect to their disease/deficiency-specific effects and not for their overall effects on morbidity and mortality. In many situations, the population-based effects have been very different from the anticipated effects; for example, the measles-preventive high-titre measles vaccine was associated with 2-fold increased female mortality; BCG reduces neonatal mortality although children do not die of tuberculosis in the neonatal period; vitamin A may be associated with increased or reduced child mortality in different situations; effects of interventions may differ for boys and girls. The reasons for these and other contrasts between expectations and observations are likely to be that the immune system learns more than specific prevention from an intervention; such training may enhance or reduce susceptibility to unrelated infections. INDEPTH member centres have been in an ideal position to document such additional non-specific effects of interventions because they follow the total population long term. It is proposed that more INDEPTH member centres extend their routine data collection platform to better measure the use and effects of childhood interventions. In a longer perspective, INDEPTH may come to play a stronger role in defining health research issues of relevance to low-income countries.

Reproductive health voucher program and facility based delivery in informal settlements in Nairobi: a longitudinal analysis.

INTRODUCTION: In Kenya, the maternal mortality rate had ranged from 328 to 501 deaths per 100,000 live births over the last three decades. To reduce these rates, the government launched in 2006 a means-tested reproductive health output-based approach (OBA) voucher program that covers costs of antenatal care, a facility-based delivery (FBD) and a postnatal visit in prequalified healthcare facilities. This paper investigated whether women who bought the voucher for their index child and had a FBD were more likely to deliver a subsequent child in a facility compared to those who did not buy vouchers. METHODS AND FINDINGS: We used population-based cohort data from two Nairobi slums where the voucher program was piloted. We selected mothers of at least two children born between 2006 and 2012 and divided the mothers into two groups: Index-OBA mothers bought the voucher for the index child (N=352), and non-OBA mothers did not buy the voucher during the study period (N=514). The most complete model indicated that the adjusted odds-ratio of FBD of subsequent child when the index child was born in a facility was 3.89 (p<0.05) and 4.73 (p<0.01) in Group 2. DISCUSSION AND CONCLUSION: The study indicated that the voucher program improved poor women access to FBD. Furthermore, the FBD of an index child appeared to have a persistent effect, as a subsequent child of the same mother was more likely to be born in a facility as well. While women who purchased the voucher have higher odds of delivering their subsequent child in a facility, those odds were smaller than those of the women who did not buy the voucher. However, women who did not buy the voucher were less likely to deliver in a good healthcare facility, negating their possible benefit of facility-based deliveries. Pathways to improve access to FBD to all near poor women are needed.

Increase in facility-based deliveries associated with a maternal health voucher programme in informal settlements in Nairobi, Kenya.

OBJECTIVE: To measure whether there was an association between the introduction of an output-based voucher programme and the odds of a facility-based delivery in two Nairobi informal settlements. DATA SOURCES: Nairobi Urban Health and Demographic Surveillance System (NUHDSS) and two cross-sectional household surveys in Korogocho and Viwandani informal settlements in 2004-05 and 2006-08. METHODS: Odds of facility-based delivery were estimated before and after introduction of an output-based voucher. Supporting NUHDSS data were used to determine whether any trend in maternal health care was coincident with immunizations, a non-voucher outpatient service. As part of NUHDSS, households in Korogocho and Viwandani reported place of delivery and the presence of a skilled birth attendant (2003-10) and vaccination coverage (2003-09). A detailed maternal and child health (MCH) tool was added to NUHDSS (September 2006-10). Prospective enrolment in NUHDSS-MCH was conditional on having a newborn after September 2006. In addition to recording mother's place of delivery, NUHDSS-MCH recorded the use of the voucher. FINDINGS: There were significantly greater odds of a facility-based delivery among respondents during the voucher programme compared with similar respondents prior to voucher launch. Testing whether unrelated outpatient care also increased, a falsification exercise found no significant increase in immunizations for children 12-23 months of age in the same period. Although the proportion completing any antenatal care (ANC) visit remained above 95% of all reported pregnancies and there was a significant increase in facility-based deliveries, the proportion of women completing 4+ ANC visits was significantly lower during the voucher programme. CONCLUSIONS: A positive association was observed between vouchers and facility-based deliveries in Nairobi. Although there is a need for higher quality evidence and validation in future studies, this statistically significant and policy relevant finding suggests that increases in facility-based deliveries can be achieved through output-based finance models that target subsidies to underserved populations.

Child growth in urban deprived settings: does household poverty status matter? At which stage of child development?

This paper uses longitudinal data from two informal settlements of Nairobi, Kenya to examine patterns of child growth and how these are affected by four different dimensions of poverty at the household level namely, expenditures poverty, assets poverty, food poverty, and subjective poverty. The descriptive results show a grim picture, with the prevalence of overall stunting reaching nearly 60% in the age group 15-17 months and remaining almost constant thereafter. There is a strong association between food poverty and stunting among children aged 6-11 months (p<0.01), while assets poverty and subjective poverty have stronger relationships (p<0.01) with undernutrition at older age (24 months or older for assets poverty, and 12 months or older for subjective poverty). The effect of expenditures poverty does not reach statistical significant in any age group. These findings shed light on the degree of vulnerability of urban poor infants and children and on the influences of various aspects of poverty measures.